A recently released study suggests that one’s race might influence one’s ability to prevent obesity. According to the June issue of the Archives of Pediatrics and Adolescent Medicine, exercise is less likely to lead to weight loss for black adolescent girls than for white adolescent girls. Both groups of girls in the study consumed the same number of calories each day and exercised at similar levels. Nonetheless, 85% of the black girls who engaged in moderate levels of exercise at 12 years old were as likely to be obese by the time they reached 14 as were those who hardly exercised at all. For white girls, the results were almost exactly reversed, with only 14% likely to become obese by age 14. As result, though they cannot fully account for their findings, the authors of the study propose that genetics were at work and that black girls may need to both exercise less and to eat less in order to lose weight.

But before we accept genetic differences between the races as an explanation for health disparities, we need to remember that although studies do make such claims, more often than not, subsequent research points toward different answers. Over the past 10 years, researchers have sought to explain the fact that 60 % more black women die from breast cancer than do white women with a theory that the tumors that strike black women are more aggressive than those affecting white women. However, more recent studies challenge this view and show that there are psychological, cultural and economic barriers to health care that account for all of the difference in survival rates between the groups.

Similarly, researchers have argued that genetic differences explain why black women, when compared to white women, are 40% more likely to die from cervical cancer. One article‘s title says it all, “Genetics explain why black women are more at risk from cervical cancer virus, say scientists,” and goes on the explain that the HPV virus, which causes cervical cancer, is more resistant to treatment in black women. But again, new research makes clear that most black women who die from cervical cancer have never been screened for the disease or have not had testing in the preceding five years. As with breast cancer, early detection and treatment, not genetics, explain why white women have a higher survival rate for cervical cancer than do black women.

Nonetheless, beliefs about genetic differences and race are deeply engrained in medicine. As Brown University professor Anne Fausto-Sterling points out in a recent Boston Review of Books article about science, race and medicine:

You can’t get a bone scan evaluated without designating a race because the formulae programmed into bone densitometers use different standards for assessing bone thinning in white, Asian, Hispanic, and African American women. The evidence supporting different standards is rarely questioned and certainly unknown to the technicians who operate the machines.

The normal functioning of black people’s lungs is typically presumed to be 10–15 percent below that of white people’s. As Lundy Braun, who studies the intersection of race and medical science and technology, has shown, the presumption stems from a poorly supported idea that blacks inherently have lesser lung capacities than whites…Some machines actually have a ‘race’ switch built into them, which technicians flip depending on what race they believe the patient to be. Pegging the lung function of blacks at a lower level means, among other things, that they have to be sicker than whites in order to qualify for worker’s compensation or other insurance for lung-related illness.

With this history in mind, before we start recommending that black girls eschew exercise because a scientific study has found that they are genetically different from white girls, we need to start asking some questions. For example, were there differences in what the young women consumed that might have accounted for their differing relationship to exercise? Did they both have equal access to gyms and good equipment and instruction on how to use it? A whole host of cultural or social factors may have played a role, and the answers to such questions will most likely show that the ability to lose weight has little to do with the genetics of race.